The two outer layers of Earth are composed primarily of - A iron B nickel C rocky material D liquid material

The two outer layers of Earth, which are the mantle and the crust, are primarily composed of rocky material. This rocky composition includes a variety of minerals, with silicate minerals being the most prevalent. The mantle, found beneath the crust, extends to depths of about 2,900 kilometers and is made mostly of silicate rocks rich in magnesium and iron. In terms of real-world application, understanding the composition of these outer layers is crucial for various fields like geology, engineering, and environmental science. For example, this knowledge helps in mineral exploration, predicting volcanic activity, and understanding the dynamics of plate tectonics, which can impact everything from construction practices to disaster preparedness.